Several processes have been known which produce propylene from an olefins-containing hydrocarbon raw material by using a zeolite-containing catalyst.
Examples known as zeolite-containing catalysts for use in the production of propylene from olefins may include a catalyst in which Ag is contained in a medium pore diameter zeolite that substantially does not contain protons and a catalyst in which the SiO2/Al2O3 molar ratio thereof falls within a range from 200 to 5000.
Although the term “olefins” covers a broad concept, the “olefins” that have hitherto been practically used as raw materials for the production of propylene are limited to the olefins having four or more carbon atoms. However, some documents describe that raw materials other than the aforementioned olefins can be used. For example, Patent document 1 describes “a method including contacting a hydrocarbon feedstock containing one or more olefinic components of C4 or greater with a crystalline silicate catalyst to produce an effluent having a second composition of one or more olefinic components of C3 or greater, the feedstock and the effluent having substantially the same olefin content” (claim 1), and also describes that “preferably, the ethylene comprises from 0.1 to 50% by weight of the hydrocarbon feedstock” (paragraph 28). Patent document 2 describes a process for producing propylene from ethylene and methanol and/or dimethyl ether. Patent document 3 describes a process for the interconversion of ethylene, propylene and butenes by using as a catalyst a molecular sieve such as SAPO-34.    Patent document 1: U.S. Pat. No. 6,388,161    Patent document 2: Japanese Patent Laid-Open No. 2006-335730    Patent document 3: U.S. Pat. No. 4,527,001